An assembly of devices that applies an electrical stimulus to all or part of the spinal cord to relieve pain (analgesia). It includes an implanted lead/electrode system located in the epidural space of the spinal cord attached to either an implanted passive electronic circuit into which signals and/or energy is inductively coupled from outside the body, or to a totally implantable self-contained system that carries its own energy source and has no inherent dependence upon external devices. It is used to treat acute and/or chronic intractable pain, where the use of drug therapy is undesirable or no longer effective.